Tag Archives: temperature controller

It was brought to my attention by a reader of Hoptomology that it would be wise to add a relay to my temperature controller build. The reason being it will render the contacts on the controller safer and extend their life. They are only rated for 10 amps and a refrigerator or freezer may draw more than that for a split second when it kicks on. Up until this point I haven’t had any issues, but it never hurts to go the extra mile when it comes to wiring and electricity. Safety should always be your first priority!

Another thing that should always be observed when using electricity with liquids nearby, is plugging the unit into a GFCI (Ground Fault Circuit Interrupter) receptacle instead of a normal one. This way you have added protection for yourself should you accidentally come into contact with your beer or sanitizer etc. and then touch the controls. Any short circuit due to the moisture will trip the GFCI and save you from a nasty shock. I tried installing a GFCI in the actual controller box, but found that it tripped the circuit quite often when it turned on, leaving my precious beer and yeast to warm up until I was able to notice. Instead, just plug the unit into a wall outlet with a GFCI, and you’re set. (Thanks for your input Henry!)

I bought the relay (Part # PB321-ND) and relay socket (Part # PB642-ND) from DIGIKEY.It cost me about $31 shipped to my door. I’m sure you could find somewhere else cheaper, like a local electronics store, but I’m guessing the connections may vary slightly. I thought I’d stick with what I know and get the parts that were suggested by Henry.

Here is the updated wiring diagram with the relay added into the circuit.

Standing over my temperature controlled chest freezer, looking down at my 2 kegs of fully carbonated Bohemian Pilsner, is a very pleasant sight indeed. I used the exact same recipe and maintained the same fermentation schedule for both a single infusion and a decoction version to see what differences could be had. (See original post: Pilsner Urquell: Decoction mash or Single Infusion?) It’s been a long time in the making. Two separate brew days, with the decoction taking me a whopping 11.5 hours (!), 14 days in primary, and another 40 days of lagering. The fact that it is ready to bottle this week, lines up perfectly with us being at the height of summer.

One of the many things I love about brewing is that I get to incorporate not only my love of beer, but my love of building things. Making crazy gadgets to suit the task at hand is something I have a lot of fun doing. Thanks to the many great articles written and shared by other home brewers, some gadgets have been tried & tested, with the rest of us benefiting from those who have gone before. This is one such gadget.

As I move deeper into brewing territory, other variables in the beer making process start to come into focus and the time comes to tinker with them to see if we can continue to improve our beer. Fermentation temperature is something that I hear many people talk about. Jamil Zainasheff has gone so far as saying it’s a “game-changer”. Wow, to say that, intrigues me. Up until now, the area of my basement that I use to ferment has a fairly steady temperature of about 68-70F, which is perfect for most ales. At one point last summer, I was fermenting a blonde ale when the compressor on our AC unit crapped out. It ended up fermenting in the 74-75F range, which is fairly high. The beer actually turned out fantastic, but I don’t know how much of a role the higher temperature played in that. Lagers, on the other hand, are different story. You need to have control over your temperatures. Since we’re now brewing 10 Gallon batches, it gives us the opportunity to split the batches into 2 five gallon carboys and try different yeasts, different fermentation temperatures and different dry hopping rates.

One way to gain control over our fermentation temperatures is to build a dedicated fermentation chamber. I lucked out a few weeks back and scored a medium sized chest freezer that someone down the street was tossing out. I suppose you could use a refrigerator, but this is what I have. A chest freezer will also hold more carboys and/or kegs. (I’m also not certain whether or not a fridge will allow you to get down to the temperatures needed to properly lager (32F-35F), but I could be mistaken.)

So you’ve got your fridge or freezer, now what? We need to override the internal thermostat and give ourselves the ability to dial in the temperatures we want. There are a few ready-to-go temperature controllers available from Johnson Controls and Ranco that seem to do the job well. They will cost you a little bit more up front, and will also cut out any of the fun building your own, but who wants that? Well, maybe some of you, and that’s totally cool. For me, I like to build stuff, so that’s what I’m going to do.